Method and apparatus for deflashing molded resilient pieces



Nov. 19, 1963 R. w. MOORE 3,110,983

METHOD AND APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES 8Sheets-Sheet 1 Filed Dec. 6, 1962 t I 3 Aw 4 222?? 1 NVENTOR I Ralph WMoore ATTORNEYS Nov. 19, 1963 R. w. MOORE 3,110,983

METHOD AND APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES Filed Dec.6, 1962 8 Sheets-Sheet 2 INVENTOR f Ralph/W. Moore Nov. 19, 1963 R. w.MOORE 3,110,983

D AND APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES 8 Sheets-Sheet 3METHO Filed Dec. 6, 1962 INVENTORI RalphWMoore ATTORNEYS Nov. 19, 1963R. w. MOORE 3,110,983

METHOD AND APPARATUS FOR DEFLASHING MOLDED RESILIEINT PIECES Filed Dec.6, 1962 8 Sheets-Sheet 4 INVENTOR:

RalPhWMoor'e ATTORNEYS R. w. MOORE 3,110,983

METHOD AND APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES Nov. 19,1963 8 Sheets-Sheet 5 Filed Dec. 6, 1962 INVENTOR:

Ralph W. Moore BY @W ATTORNEYS R. w. MOORE 3,110,983

METHOD AND APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES Nov. 19,1963 8 Sheets-Sheet 6 Filed Dec. 6, 1962 INVENTOR Ralph WIMOorc BY Wwwfijg ATTORNEYS R. w. MOORE 3,110,983

METHOD AND APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES Nov. 19,1963 8 Sheets-Sheet 7 Filed Dec. 6, 1962 Q\ m A INVENTORI Ralph W MooreBY ATTORNEYS Nov. 19, 1963 R. w. MOORE 3,110,983

METHOD AND APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES 8Sheets-Sheet 8 Filed Dec. 6, 1962 INVENTOR! Ralph W.M00I"6 MW ATTORNEYSUnited States Patent 3,110,983 METHOD AND APPARATUS FOR DEFLASHINGMOLDED RESILIENT PIECES Ralph W. Moore, Hagerstown, Md., assignor to ThePangborn Corporation, Hagerstown, MIL, a corporation of Delaware FiledDec. 6, 1962, Ser. No. 242,750 18 Claims. (Cl. 51-9) The presentinvention relates to a method and apparatus for removing trimmings,flashings, fins, etc. from molded resilient pieces particularly thosepieces molded or otherwise formed from rubber.

Heretofore, the excess rubber flashing or trim has been removed fromrubber molded parts by simultaneously freezing the parts and tumblingthem in a suitable tumbling barrel assembly. In these barrel assemblies,an abrasive media is used which is tumbled along with the rubber pieces.This barrel operation has proved to be unsatisfactory in many instancesin that many rubber molded pieces have certain areas or surfaces whichare more or less hidden and not accessible to the abrasive media. Thisunsatisfactory result occurs since the abrasive media must be of acertain size and mass to be effective. Usually, such media is too largein size to satisfactorily remove the excess trim from the abovementioncdcertain hidden areas and surfaces which are found in many parts whichhave complex shape.

Furthermore, in the above tumbling barrel techniques the entire piecebeing dellashed is frozen because of the length of time required incompletely dcflashing by the tumbling method. In view of the above, thebarrel method for tumbling the parts thus required unnecesarilyexpensive freezing gas consumption and machine time. Also, stress crackstend to develop in the completely frozen parts. In addition, certainprojecting or edge portions of the pieces which are slightly thickerthan the flashing and should remain with the pieces are also broken offsince the entire piece is so completely frozen.

it is thus seen that the tumbling barrel method has proved to becompletely unsatisfactory for general use in dellashing molded rubberparts.

Recently. a method and apparatus (Patent No. 2,996,- 846) has beendeveloped wherein the rubber pieces to be trimmed are loaded in a troughshaped endless conveyer which is enclosed in an insulated housing. Asthe rubber pieces are tumbled in the trough shaped conveyer, the piecesare subjected to a spray or blast of a freezing medium such as Dry Iceparticles or liquid carbon dioxide. This freezing step is timed so as tobring about a differcntial freezing of the pieces wherein the fins ortrimming of the pieces are frozen but the main body of the piece itselfis not substantially frozen. In this differentially frozen condition,the pieces are then subjected to a blasting operation wherein abrasivemedia is propelled at great force against the frozen rubber pieces asthey are tumbled in the trough conveyor whereby the abrasive removesonly the excess trimming on the pieces. In view of the relatively smallsize of the steel shot abrasive generally used, any generallyinaccessible surface or area of the excess trimming of the rubber piecesis subjected to the abrasive treatment.

With the above latter arrangement. the disadvantages mentioned above inconnection with the barrel tumbling operation are substantiallyeliminated.

One object of the present invention is to provide a new and novelapparatus and method having improvements over the above describedapparatus and methods used heretofore, particularly with respect to thesecond method and apparatus described above.

Other objects and advantages of the invention will be- 3,110,983Patented Nov. 19, 1963 come more apparent from a study of the followingdescription and drawings wherein:

FIGURE 1 is a perspective partially broken away of the overall apparatusof the present invention;

FIGURE 2 is a perspective of the apparatus of the present inventionshowing more particularly the front of the apparatus;

FIGURE 3 is a view similar to that of FIGURE 2 showing the door to thehousing of the apparatus in raised position and with the rubber pieceloader mechanism in loading position;

FIGURE 4 is an interior view of the housing taken from one side thereof;

FIGURE 5 is a detail of the apparatus shown in Ft- URES 1 through 4taken from the opposite side to that of FIGURE 4;

FIGURE 6 is a view on an enlarged scale of the trough shaped conveyersupported within the housing, and wherein the rubber pieces are treatedboth with the freezing medium and the abrasive material;

FIGURES 79 are diagrams of the liquid carbon dioxide distributionsystem;

FIGURES 10, 10A, 11 and 11A show molded rubber pieces before and afterthe trimming operation.

Referring now to FIGURES 1 through 5, which show the general makeup ofthe apparatus, an overall housing 1 is provided and serves as adehumidifying or refrigeration chamber in which the operating units ofthe apparatus are housed. As shown better in FIGURES l and 4, thehousing 1 has formed heavy walls. The wall panels are preferably formedof inner and outer sheets of plywood which form a sandwich structurewith insulotion such as fiberglass positioned between the plywoodsheets. The exterior of the housing 1 is clad with galvanized steelbackers or sheets. A refrigeration evaporator 2 is supported in theupper right hand corner of the housing (see FIG. l).

In the front wall of the housing, there is a loading and unloadingdoorway 3 for loading and removing the rubber parts from within thehousing 1. As seen better in FIGURES 1 3, the door 5 of the housing 1 israised and lowered in tracks 7 by the hoisting mechanism generallyindicated at 9 to expose and close off doorway 3.

As better seen in FIGURE 3, the lower portion or closed position portionof tracks 7 curves and extends inwardly from the upper portion or openposition of the tracks 7. With this arrangement, a good tight seal isprovided between door 5 and doorway 3 when the door is in the closedposition.

For loading and unloading the rubber pieces from a point externally ofthe housing 1, through the doorway 3 and into the freezing and abrasivetreating area which will be described later, there is provided as betterseen in FIGURES 1-3 a loading bucket 11 pivotally supported on arms 13which are in turn pivotally supported on a bracket 15 mounted in fixedmanner on drive shaft 17. Drive shaft control 19 rotates the shaft 17 toin turn raise the bracket 15, the bucket supporting arms 13 and thebucket 11 supported thereby to a position adjacent the top of the opendoor-way as seen in FIGURE 3. A side guide arm 21 pivotally connected tothe housing 1 and an arm 13 guides or pulls the bucket 11 inwardlywithin the doorway 3. When the bucket is raised to this uppermostposition, pressure cylinder 23 connected to the bucket support and thebottom of the bucket 11 is actuated to extend its shaft 25 connectedwith the bottom of the bucket to tip the bucket as shown in FIGURE 3whereby the rubber pieces loaded in the bucket will be discharged intothe freezing and abrasive treating area. After discharging its load, thepiston 25 is then retracted and the drive shaft 17 is rotated in theopposite direction to in turn lower the bracket 15, the arms 13 and thebucket 11 to its original station as shown in FIGS. 1 and 2. The door 5opens automatically during the loading operation and is closed duringthe treating steps. Once the articles are deflashed and ready forunloading, door 5 is auto matically opened again.

The above operation of the bucket loader and door 5 is included as apart of a cycle which is automatically controlled through the controlpanel 27 allixed to the front face of the housing 1. The complete cyclewill be ex plained later. The pressure cylinder can be solenoidoperated.

The rubber pieces are received from loading bucket 11 by a trough shapedendless belt type conveyor 29 as shown better in FIGURE 5 and especiallyFlGURE 6. The conveyor 29 is formed of metal bars or slats 31 (FlGURE 6)which extend transversely of the conveyer travel and are connected attheir ends to a continuous sprocket chain 33 (FIGURE 5). The conveyorrotates around a front pair of guide sprockets 35 and a pair of reardrive sprockets 37 (FIGURE 5). A pair of guide disks 39 are rotatablymounted in side walls 41 which onclose the sides of conveyor trough areato provide contact with the slats 31 of the upper deck of the conveyer29 to compel the conveyer 29 to follow a concave path which resembles atrough laterally inclined so that it faces the doorway 3.

The operation of the conveyer 29 is part of the controlled from thepanel 27. also be formed of a wire mesh belt instead of the bars orslats as shown. The conveyor area also includes a door 46 (see FIGS. 5and 6) which is opened automatically through control panel 27 during theloading and unloading operation but which is closed during the freezingand abrasive treatment. Briefly, this door consists of an upper rigidportion having a lower flexible portion. The door 46 is supported byrollers in door tracks 46' which bend inwardly adjacent the bottom ofthe tracks. Since the lower portion of the door 46 is flexible, itfollows the curved pathway defined by the lower curved portion of thetracks. The tracks 46' for the door 46 extend upwardly above the roof ofthe conveyer area to accommodate the door in its opened position. Thesestructural details of the door are better shown in Patent No. 3,048,947;how ever, other suitable doors can be used.

After the rubber pieces 42 (see FIGURE 6) are loaded in the conveyer andbefore they are trimmed or deflashed, they are treated with a freezingmedium 43 which can be liquid carbon dioxide. pulverized Dry Ice orother suitable freezing mediums such as liquid nitrogen. The conveyor 29is in operation during the freezing step whereby the pieces 42 aretumbled and turned to expose all surfaces to the freezing action.

The freezing medium used is supplied to the nozzles 45 by a commonheader 47 extending through and supported by the side walls 41 enclosingthe conveyer area.

Again, the application of the freezing medium 43 to the work pieces 42occurs in a definitely timed cycle con trolled by or through controlpanel 27.

In the freezing operation, the rubber pieces 42 are differentiallyfrozen. This means that the excess trim ming, flashing. etc. is frozento a brittle state while the thicker portions of the rubber pieces arenot completely frozen and therefore still retain some of theirresiliency. With this arrangement, the brittle thin flashings are easilyremoved by the abrasive action whereas the thicker portions of thepieces are not damaged or otherwise abused by the abrasive action. Theduration of the freezing step of the cycle will vary for different sizeor type of rubber pieces being treated.

After the rubber pieces have been differentially frozen in the mannerexplained above, they are then exposed to the next step of the cyclewhich is the abrasive treating cycle. As shown better in FIGS. 4 and 5 arotary wheel 50 is supported in a housing 52 attached to the roof-topcycle The endless conveyer may or wall 44 which joins the side walls 41of the conveyer area. to cover the top of the conveyer area. The wheel50 is rotated at high speed by motor 53 to propel abrasive media such asfine steel shot through an opening 54 in the roof top 44 and against thefrozen rubber pieces supported in the trough shaped conveyer. During theabrasive applying step, the plug 54 is automatically witldrawn from theopening 54. A battle plate 55 extending horizontally from the freezingmedium supply header 47 prevents abrasive from striking the header 47.The abra sive media is supplied to the blasting wheel 50 through storagebin 56 connected by passageway 57 to the Wheel itself.

For further detailed description of the rotary blast. wheel itself,reference is made, for instance, to Patents Nos. 2,869,289 and 2,732,666as well as copending patent applications Serial Nos. 221,100, filedSeptember 4, 1962, and 195,698, filed May 18, 1962. Any type of wheelassembly may be used however.

it should be noted, as mentioned above, that during both the freezingstep and the abrasive action step, the sprockets 35 and 37 are driven bya suitable motor drive mounted externally of the side walls 41 whichenclose the conveyer area. This action causes the rubber pieces totumble, rotate and otherwise change position whereby all surfaces of thepieces 42 are adequately exposed or subjected to both the freezing andabrasive treatment.

After the abrasive action has ceased, both the outer door 5 and theinner door 46 are automatically raised to open position. The directionof. travel of the conveyor 29 is reversed and as seen in FlGURES 5 and 6the rubber pieces 42 drop onto a slide plate 6t) from which point theyslide outwardly through the doorway 3 onto the unload conveyor til (seeFIGURES 1 and 2). This slide plate of) is automatically moved intoposition as shown in FlGURES l, 5 and 6 when the unloading step of thecycle begins. After the rubber pieces are unloaded, the slide plate isthen automatically retracted away from the conveyor 29 to permit thinner door 46 to close. This extension and retraction operation iscontrolled preferably by a carbon dioxide pressure cylinder operatedthrough the control panel 27. The conveyor 62 is of the vibrating typedriven by vibrator motor 63 attached thereto as shown in FIG. 3 andhaving a perforated top deck whereby any abrasive which is unloaded withthe rubber pieces is shaken from the pieces. This abrasive drops throughthe perforations onto a solid plate positioned below. This type ofconveyor is important in that the abrasive must be removed before therubber pieces begin to thaw out. If such is not done, the pieces collectmoisture as they thaw after which the abrasive cannot be removed fromthe pieces which causes undesirable rust spotting and loss of abrasive.

Any suitable vibrating conveyor can be used here as long as it followsthe general structure indicated above.

The abrasive and trim or flash that has been removed from the rubberpieces 42 in the trough conveyor 29 drops through the slats 31 whichmake up the conveyor 29 and onto a screen slide or chute 7d (FIGURE 5)which permits only the abrasive and liner pieces of flashing to pass.This abrasive drops onto a screen conveyer (not shown) or otherconveying means and is fed to a scalping drum 72 (see PM}. 5). In thescalping drum, the abrasive drum, the abrasive is further refined fromthe removed trim or flash with the flash discharged through the reluscdischarge 74 (FEGURE 1) into a collection box 76 which can be removedand emptied by the user.

The specific structure of the scalping drum is described in Patent No.2,771,189 and patent application Serial No. 22,588, filed April 15,1960. From the scalping drum 72, the abrasive from which the largerpieces of trim or flash have been removed is passed into an elevatorwhich raises the abrasive upwardly to a separator 77 of an air washtype. The supply air for the separator is provided by the suction airbeing discharged from the dust collector which is described hereinafter.Here, the abrasive passes through a steam of air whereby the fins andother light-weight contamination are removed. The specific structure ofthe separator can be that shown in Patent No. 2,771,189 and patentapplications Serial No. 214,271, filed August 21, 1962, or Serial No.22,588, filed April 15, 1960.

From the separator 77, the abrasive then passes down into the storagebin 56 for the abrasive from which it passes through conduit 57 to theabrasive wheel 50. The conduit 57 includes a suitable metering and purgegate assembly (not shown) for metering the abrasive to the wheel. Thisgate is disclosed and claimed in copending patent application Serial No.214,271, filed August 2, 1962. Briefly, it is formed of an elementhaving a blade extending therefrom which meters the flow of abrasive.When jammed, an air cylinder operated directly by a depressable buttonfrom the control panel 27 rotates the element to move the blade out ofjammed position. At the same time another blade on the element movesinto metering position.

To further clean the abrasive, if necessary, a portion of the abrasiveis branched off from the storage bin 56 through a feed pipe 83 to ashaker conveyor similar to the unload conveyor 62 described abovewherein the abrasive passes through a screen onto a solid platepositioned below the screen from which point it is returned to the blastwheel 50 or storage bin 56.

From the separator 77, the moving air stream containing thecontamination removed from the abrasive in the separator 77 passesthrough delivery pipe 79 into a dust collector or filter assembly 81.

The dust laden air stream is then filtered through a series of dust bags(not shown) with the air stream being drawn by the fan 87 mounted on topof the dust collector. The air is discharged through opening 89.Suitable dust collectors can be found in Patents Nos. 3,053,031;2,667,233; 2,876,862; and copending patent application Serial No.825,097, filed July 6, 1959.

Contaminated air is also fed to the dust collector 81 through outlet 90leading off from the area adjacent the conveyer 29.

It should be pointed out that when loading and unloading occurs, theventilation of the trough conveyor through outlet 90 is cut off bydamper 92 located in line 90. This prevents drawing warm air fromoutside the housing into the cooled system. The damper 92 must be openduring the blasting operation to provide ventilation. However, it isalso closed during the liquid carbon dioxide application against therubber work pieces 42 to prevent drawing the cooling air thusinterfering with the freezing operation. The damper operation iscontrolled by a carbon dioxide valve which is incorporated into theoperation cycle through control panels 27. When the damper 92 is closed,the air coming from the conveyer 29 area is by-passed to draw air fromthe housing interior in order to maintain a constant flow to the airseparator 77. Damper 94 positioned atop dust collector S1 is also closedand by-passed to the housing interior in a timed cycle as will beexplained later.

With regard to the liquid carbon dioxide feed and circulation systemreference is made to FIGURES 79 of the drawing. FIG. 7 shows a gravitysystem whereby the supply tank 100 is held at a higher level than thesolenoid operated discharge valves 45. FIG. 8 shows a recirculating typewhere a recirculating pump 102 continually circulates the liquid CO fromthe supply tank 100 past the discharge valves 45, and back to the supplytank. FIG. 9 shows a reduced pressure system whereby liquid CO is takenfrom the storage tank 100 and held in a smaller control tank 104 nearthe injection valves 45 at :a pressure lower than the pressure of thesupply tank.

With all three of the systems shown in FIGS. 79, a check valve allowingflow only in the direction of the supply tank is provided. The vapor COas it converts from the liquid, rises and enters the vapor return partof the loop. When a check valve is not used, the solenoid injectionvalves draw both from the liquid CO line and from the vapor return line,thereby entraining vapor with the liquid. Where the check valve is used,the injection valves draw only dense liquid CO from the supply tank andpre-determined time cycles of injection can be used because theB.t.u.s/sec. of injection are constant. The check valve 106 is providedto operate in the above manner for reasons given below.

Liquid CO in the so-callcd low pressure" system as commonly used forindustrial applications is held in the storage tank at about 300p.s.i.g. The pressure in the storage tank is maintained by a mechanicalrefrigeration system which controls the temperature.

Flash freezing of rubber and plastic parts and the maintaining of thefrozen flash during the heat generated by a blast cycle is accomplishedby heavy flows of CO for short time intervals. Normally, when the warmparts are put into the deflashing machine, a fairly long heavy COinjection in the order of 30 sec. to l min. is used to reduce thetemperature of the entire load of work parts. When the flash is frozen,steel abrasive is projected at high velocity against the work to breakoft the flash. This mechanical work induces a heat build-up, so theblast is interrupted at regular intervals and very short bursts ofliquid CO are injected to counteract the heat of the blast operation.

It has been found that liquid C is a very unstable material because ittends continuously to convert to vapor. It is this phenomena which makesliquid CO 21 good refrigerating material because it absorbs a tremendousheat during the conversion. However, when you hold the liquid CO againstthe head of the injection valve between injections, a portion of itconverts to vapor in the line, and therefore, loses its refrigeratingaction when injected against the work. If the injection valves are heldopen long enough all the vapor will be purged from the line and thenliquid CO will be injected. During the automatic cycle of a freezedeflashing machine, however, the injections are normally of such shortduration that most of the injection time is used purging the vapor fromthe line and very little liquid CO is actually injected. This has beenfound to cause erratic temperature control in the work because of thevariable amounts of vapor which accumulate.

FIGS. 10, 10A, 11 and 11A show freshly molded rubber articles 150 whichstill have the flash 152 attached thereto. The molded article 150 isalso shown after the flash has been removed.

The various mechanisms described above throughout the application arepreferably operated by carbon dioxide valves wherever possible. Thesevalves are connected with the control panel to operate in a timed cycle.

The cyclic operation of the assembly described above is as follows:

(1) Doors closed-machine shut down;

(2) Press cycle start button (panel 27);

(3) Abrasive system starts and remains running for successive cycles;abrasive recirculating starts;

(4) Room and conveyor (5, 46) doors open," exhauster stops (if running);work conveyer reverses to unload; damper (92) by-passes to room,collector shaker (62) starts; damper 94 closes; after 5 seconds,collector shaker (62) stops;

(5) Work conveyor (29) forward-loader up and down; approximately 10seconds;

(6) Room and conveyor (5, 46) doors close damper (94) opens, exhaust(90) starts;

(7) Primary freeze on, holds damper 92 by-pass to room;

(8) Blast wheel (50) starts (no abrasive yet);

(9) Primary freeze off, blast one; abrasive recirculating stops; damper(92) returns to normal;

(10) Each secondary freeze, damper 92 by-passes to room; last oil eachtime;

(11) Blast timer times outblast shuts off; abrasive recirculatingstarts;

(l2) After 60 seconds for draining abrasive from load,

work conveyor stops and cycle ends;

(13) Abrasive system and exhauster (98) remain run ning, abrasiverecirculating operating; dampers 2 and 94) in normal position;

(14) To repeat cycle, press cycle start button and sequence repeats from#4 above;

(15) Damper gate 92 When operated to by-pass, disconnects conveyor (29)ventilation from exhaust separator-ventilation remains on;

(16) Damper gate 94 when operated disconnects exhauster from unloadshaker (62) separator (77) and conveyor (29);

(17) Damper gate 92 operates to by-pass whenever doors are open orfreeze is turned on; and

(i8) Damper gate 94 closes whenever load doors are open.

Obviously iany modifications and variations of the present invention arepossible in the light of the above teachings. it is, therefore, to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. Apparatus for del'lashing molded resilient pieces comprising adehumidifying housing, means supported Within the housing forsimultaneously supporting and turning said molded pieces havingflashing, a freezing medium applicator means Within said housingadjacent said piece supporting and turning means for applying freezingme dium to said pieces to lower the temperature of said molded pieces,abrasive blasting irneans supported within said housing adjacent saidpiece supporting and turning means for propelling abrasive against saidcooled work pieces to remove the flashing therefrom, means adjacent themolded piece supporting and turning means for collecting the usedabrasive and the removed flashing, means for separating the removedflashing from said used abrasive, means for conveying the separated usedabrasive to a point for reuse by the blasting means, a dust collectorpositioned within said housing, ventilating means leading off from saidmolded piece supporting and turning means which ventilating means isconnected with said dust collector. and means within said ventilatingmeans for teimporarily closing off said ventilating means from said dustcollector.

2. The apparatus of claim 1 wherein an air wash separator is alsoprovided within said housing for separating finer contamination from theused abrasive.

3. The apparatus of claim 2 wherein a ventilator leads off from said airwash separator and is connected to the dust collector.

4. The apparatus of claim 1 wherein said piece supporting and turningmeans is an endless belt type conveyer assembly formed of spaced andtransversely extending slats, the rear support for the belt beingrotatably supported at a point higher than the front rotatable beltsupport, side and top walls enclosing said belt, rotatable end discssupported in the side walls which are urged against the top flight ofsaid belt to form a trough in the belt, a vertically moving doorprovided for the loading and unloading end of said belt which door fitsclose against the side and top walls when lowered in position, and themeans for applying a freezing medium is so positioned to apply saidmedium against the top flight of said belt.

5. The apparatus of claim 4 wherein a retractible slide plate issupported in front of said lower rotatable support for said belt, andcontrol means are provided for moving the plate into position adjacentthe belt when the belt travel is reversed for unloading the pieces.

6. The apparatus of claim 1 wherein said housing contains a doorway, avertically movable door in said doorway, a work piece bucket loadersupported externally of said housing adjacent said doorway, verticallyreciprocating support means for said bucket loader, and reciprocatingmeans connected with said bucket loader and support for tipping saidbucket, said support and tipping means cooperating to move the bucketloader into and through the housing doorway to a discharge positionabove said piece supporting and turning means.

7. The apparatus of claim 1 wherein refrigerating means are provided insaid housing for cooling the area enclosed thereby.

8. The apparatus of claim 1 wherein a remote control means is providedfor operating the units in a timed cycle.

9. The apparatus of claim 6 wherein a vibrating conveyer-separator meansis provided externally of the housing doorway for receiving the piecesdischarged from the housing for separating abrasive from the pieces andto convey the pieces to a collection point.

10. The apparatus of claim 6 wherein a purge gate is provided adjacentsaid blasting means to release any jammed abrasive being fed to theblasting means.

11. A method for deflashing molded resilient pieces comprising loadingsaid pieces into a dehumidificd treat ing area, closing off saidtreating area from the surrounding atmosphere, ventilating said treatingarea, continuously turning and rotating said pieces in said treatingarea, applying a freezing medium against said pieces as they are rotatedto freeze the flashing of the pieces, shutting off the ventilationduring the freezing step, terminating the freezing medium application,blasting said pieces with abrasive to remove the frozen flashingtherefrom, resuming the ventilation during the blasting operation,terminating the abrasive blasting, collecting the removed flashing andused abrasive, separating the removed flashing from the used abrasive,returning the abrasive for reuse in the blasting operation, unloadingthe dcflashed pieces from the dehumidified treating area, and shuttingoff the ventilation during the unloading step.

12. The method of claim 11 wherein the separated abrasive is furtherseparated from finer contamination.

13. The method of claim 11 wherein liquid carbon dioxide is used as thefreezing agent.

14. The method of claim 11 wherein the treating area is dehumidified byrefrigeration means.

15. The method of claim 11 wherein the abrasive blasting step isperiodically interrupted by said freezing medium application step.

16. The apparatus of claim 1 wherein a freezing medium vapor return lineis provided in said freezing medium applicator means, and a check valveis installed in said return line to limit the travel of vapor therein.

17. The apparatus according to claim 7 wherein automatic control meansis provided for operating the units in a timed cycle.

18. The method according to claim 11 wherein the treating area isdirectly ventilated to a suction conduit.

References Cited in the file of this patent UNITED STATES PATENTS2,533,653 Winkeljohn Dec. 12, 1950 2,682,732 Hanrahan et al. July 6,1954 2,719,387 Fahrney Oct. 4, 1955 2,881,571 Granata Apr. 14, 19592,996,846 Leliaert Aug. 22, 1961 3,008,274 Welter Nov. 14, 19613,048,947 Fahrney et al Aug. 14, 1962 3,049,837 Freeman Aug. 21, 19623,081,580 Powell et a1 Mar. 19, 1963

1. APPARATUS FOR DEFLASHING MOLDED RESILIENT PIECES COMPRISING ADEHUMIDIFYING HOUSING, MEANS SUPPORTED WITHIN THE HOUSING FORSIMULTANEOUSLY SUPPORTING AND TURNING SAID MOLDED PIECES HAVINGFLASHING, A FREEZING MEDIUM APPLICATOR MEANS WITHIN SAID HOUSINGADJACENT SAID PIECE SUPPORTING AND TURNING MEANS FOR APPLYING FREEZINGMEDIUM TO SAID PIECES TO LOWER THE TEMPERATURE OF SAID MOLDED PIECES,ABRASIVE BLASTING MEANS SUPPORTED WITHIN SAID HOUSING ADJACENT SAIDPIECE SUPPORTING AND TURNING MEANS FOR PROPELLING ABRASIVE AGAINST SAIDCOOLED WORK PIECES TO REMOVE THE FLASHING THEREFROM, MEANS ADJACENT THEMOLDED PIECE SUPPORTING AND TURNING MEANS FOR COLLECTING THE USEDABRASIVE AND THE REMOVED FLASHING, MEANS FOR SEPARATING THE REMOVEDFLASHING FROM SAID USED ABRASIVE, MEANS FOR CONVEYING THE SEPARATED USEDABRASIVE TO A POINT FOR REUSE BY THE BLASTING MEANS, A DUST COLLECTORPOSITIONED WITHIN SAID HOUSING, VENTILATING MEANS LEADING OFF FROM SAIDMOLDED PIECE SUPPORTING AND TURNING MEANS WHICH VENTILATING MEANS ISCONNECTED WITH SAID DUST COLLECTOR, AND MEANS WITHIN SAID VENTILATINGMEANS FOR TEMPORARILY CLOSING OFF SAID VENTILATING MEANS FROM SAID DUSTCOLLECTOR.